Dennis
I run steel tracks on my foam filled tire on my 773 and have had no problems.
The only drawback I see is that I used to air down my rear tires to make joining the track easier, and that is not an option now. Sure is nice to never have a flat. They do ride somewhat on the stiff side, but not too bad. Main drawback is the cost. My loader came with them to but I just check the price here in canada and was quoted, 339 for foam, plus 22.00 for a new tube and 185 for a new tire. So at @ $550 a corner its definite spendy, probly less in the US everthing else seem to be that way.
I also run that green "slime" sealant http://www.slime.com/ in my 553 tires and have had no flats to date. Have not noticed any punctures though. It is supposted to seal a 1/4" hole.
Ken